A mashup is an integration of information from multiple sources, such as web services. For example, cartographic information from a mapping web service can be combined with real estate information to create a web-based mashup that provides directions and location information for homes that are for sale.
Creating and modifying mashups, however, can be difficult. To create or modify a mashup a software developer often has to be involved and skilled in asynchronous programming, data structures, and various programming languages. This limits the widespread use of mashups.